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NorthGeorgiaWX

Hurricane Dorian (05L)

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This is where I will post information regarding Dorian. Feel free to comment, add to, or just read.
Most everything here updates automatically, but always check the date and time on the image to be safe. I won't update this original post since it should update automatically. I will make my updates as comments below the post.

 

NHC Track
113258_5day_cone_with_line_and_wind.png

 

Wind Speed Probabilities
113258.png

 

Arrival Time for TS Force Winds

113258_earliest_reasonable_toa_34.png

 

Surface Wind Field with Warnings
113258_current_wind_sm.png

 

Key Messages
113258_key_messages_sm.png

 

 

Caribbean Sea Analysis
CAR_latest.gif

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August 26, 5 AM Update

Tropical Storm Dorian Discussion Number   8
NWS National Hurricane Center Miami FL       AL052019
500 AM AST Mon Aug 26 2019

Satellite images indicate that deep convection associated with
Dorian continues to fluctuate curtailing significant strengthening

likely due to intrusions of dry airThe overall trend, however,
suggests that Dorian is gradually getting better organized with its
cloud pattern consisting of a compact central dense overcast and

some broken outer bandsThe initial intensity is nudged up to 50
kt based on a blend of the satellite intensity estimates.  Dorian
remains a small storm with its tropical-storm-force winds estimated
to extend no more than 40 n mi from the center.


During the next couple of days, as Dorian moves through the Windward
Islands and across the eastern Caribbean, slow strengthening seems
likely due to low wind shear conditions and high SSTs.  However, the
surrounding dry air around the cyclone should continue to limit the

rate of intensificationWhen Dorian approaches Hispaniola in
about 3 days, the models show an increase in shear and those
stronger environmental winds and the potential interaction with the
rugged terrain of Hispaniola suggest that significant weakening is

likely.  The NHC intensity forecast remains between the dynamical
models that show little or no strengthening and the statistical DSHP
and LGEM that show significant intensification.  It should be noted
that the GFS and ECMWF have been very consistent in showing Dorian
dissipating over the Caribbean Sea.  Due to the wide range of the
model solutions, the NHC intensity forecast remains of low
confidenceIt should be noted that compact tropical cyclones like
Dorian are often challenging to predict.

Dorian is moving westward at 12 kt steered by a subtropical ridge
to its north.  The storm should turn west-northwestward today and
then northwestward on Wednesday when the cyclone gets closer to the
eastern end of the mid- to upper-level low.  The track models have
shifted slightly to the right or north this cycle, and the NHC
track forecast has been nudged in that direction.

Key Messages:

1. Dorian is expected to bring tropical storm conditions to
portions of the Lesser Antilles, where tropical storm watches and
warnings are in effect.  Residents in these areas should refer to
advice from local government officials and products from their
local meteorological service for additional information.

2. Dorian is expected to produce 2 to 4 inches of rain in Barbados,
the Windward Islands, and Dominica, with isolated amounts as high as
6 inches.

3.  While it is too soon to determine the specific time or
magnitude of possible direct impacts in Puerto Rico, the Virgin
Islands, or Hispaniola, interests in those areas should monitor the
progress of Dorian and watches could be required later today.

FORECAST POSITIONS AND MAX WINDS

INIT  26/0900Z 11.9N  56.4W   50 KT  60 MPH
 12H  26/1800Z 12.4N  58.2W   50 KT  60 MPH
 24H  27/0600Z 13.2N  60.3W   55 KT  65 MPH
 36H  27/1800Z 14.4N  62.4W   55 KT  65 MPH
 48H  28/0600Z 15.5N  64.5W   60 KT  70 MPH
 72H  29/0600Z 18.0N  68.4W   65 KT  75 MPH
 96H  30/0600Z 20.8N  71.6W   30 KT  35 MPH
120H  31/0600Z 23.0N  75.0W   30 KT  35 MPH

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Interesting, knowing the storm will not go perfectly up the center of the cone but left or right of it.. so many  dynamics in play.. so interesting!!

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12 minutes ago, MNW said:

Interesting, knowing the storm will not go perfectly up the center of the cone but left or right of it.. so many  dynamics in play.. so interesting!!

And why that cone gets larger as you go out in time... the track errors grow larger. There is uncertainty right now, so it pays to watch for small changes in the models. Trends are important. 

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The GFS looks to be a bit of an outlier for the time being. It's solution looks a bit strange also, all but dissipating the storm before it even gets to Hispaniola. Old GFS probably showed a worst case scenario at 12z. Hwrf has been fairly consistent its last few runs and Euro jumped on board last night. And there was a big jump in the ensembles on how many members got past Hispaniola. If it sticks to its guns at 12z I would at least raise my confidence on something surviving past the islands. Then it all comes downs to conditions and steering currents on the other side. 

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44 minutes ago, KingOfTheMountains said:

The GFS looks to be a bit of an outlier for the time being. It's solution looks a bit strange also, all but dissipating the storm before it even gets to Hispaniola. Old GFS probably showed a worst case scenario at 12z. Hwrf has been fairly consistent its last few runs and Euro jumped on board last night. And there was a big jump in the ensembles on how many members got past Hispaniola. If it sticks to its guns at 12z I would at least raise my confidence on something surviving past the islands. Then it all comes downs to conditions and steering currents on the other side. 

Latest model runs

AL05_2019082612.thumb.png.140815181a396cac4d138fa582855c43.png

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If she takes the track north of the island, I begin to worry, because regardless of how strong it gets, the tracks are still toward Florida.

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Monday, August 26 - 11am Update

Tropical Storm Dorian Discussion Number   9
NWS National Hurricane Center Miami FL       AL052019
1100 AM AST Mon Aug 26 2019

Satellite imagery indicates that Dorian's convective and outflow
pattern have continued to improve, with a narrow poleward outflow
channel now apparent in water vapor images
. Passive microwave
imagery has shown a persistent low-level eye-like feature
along with an intermittent mid-level eyewall forming that quickly
erodes due to mid-level dry air entrainment. The initial intensity
of 50 kt is based on a blend of satellite intensity estimates
ranging from 45 kt to 56 kt from TAFB, SAB, and UW-CIMSS ADT and
SATCON.

The initial motion is now west-northwestward or 285/12 kt. Dorian is
expected to continue moving west-northwestward today through Tuesday
night
as the cyclone moves around the southwestern periphery of a
deep-layer subtropical ridge situated to its north. On Wednesday,
Dorian is forecast to turn northwestward toward a weakness in the
ridge, which could allow the cyclone to pass near or between
western Puerto Rico and the eastern Dominican Republic. By late
Thursday and Friday, all of the model guidance indicates that the
ridge will build back as an upper-level trough/low weakens and lifts
out to the north, which should result in Dorian turning back toward
the west-northwest in the vicinity of the Bahamas
. The new NHC track
forecast has been nudged slightly to the right or north of the
previous one and lies close to the tightly clustered consensus
models HCCA, FSSE, TVCN, and TVCX.

The intensity forecast is less straight-forward than the track
forecast. Environmental conditions, except for the abundance of dry
mid-level air surrounding and occasionally being entrained into
Dorian's inner-core region, would favor at least steady
strengthening due to very low vertical wind shear, SSTs of at least
29C, and the small overall circulation and inner-core wind field.
The recent development of a poleward outflow channel and possible
development of an equatorward channel would also support
strengthening. However, until Dorian closes off a solid eyewall,
only slow strengthening is likely
. Anticipating when an eye will
form is challenging, but Dorian could be a hurricane by the time it
reaches the Windward Islands
. The intensity forecast has been
adjusted upward from the previous advisory, but is not as high as
the statistical-dynamical SHIPS and LGEM intensity models.
Interaction with Hispaniola and possibly Puerto Rico should result
in some weakening in 72-96 hours, followed by restrengthening on day
5 when Dorian will be moving over the very warm waters in the
Bahamas in low shear conditions. Given the unknown degree of
interaction with Hispaniola, the intensity forecast at days 4 and 5
is of very low confidence.

Key Messages:

1. Dorian is expected to bring tropical storm conditions to portions
of the Lesser Antilles tonight and Tuesday, where tropical storm
watches and warnings are in effect. Hurricane conditions are also
possible in portions of the Windward Islands, and a hurricane watch
has been issued for St. Lucia
. Residents in these areas should refer
to advice from local government officials and products from their
local meteorological service for additional information.

2. Dorian is expected to produce 3 to 8 inches of rainfall from
Martinique to St. Vincent, including Barbados, with isolated totals
as high as 10 inches in portions of the northern Windward Islands
.

3.  The risk of direct impacts from wind and rainfall has increased
for Puerto Rico and Hispaniola. Interests in those areas should
monitor the progress of Dorian and tropical storm or hurricane
watches will likely be required later today.

4. Any potential impacts from Dorian in the Bahamas and Florida
later this week are highly uncertain, given the potential for the
system to interact with the high terrain of Hispaniola.

FORECAST POSITIONS AND MAX WINDS

INIT  26/1500Z 12.3N  57.7W   50 KT  60 MPH
 12H  27/0000Z 12.9N  59.4W   55 KT  65 MPH
 24H  27/1200Z 13.9N  61.4W   60 KT  70 MPH
 36H  28/0000Z 15.1N  63.5W   65 KT  75 MPH
 48H  28/1200Z 16.4N  65.6W   70 KT  80 MPH
 72H  29/1200Z 19.2N  69.3W   70 KT  80 MPH...NERN HISPANIOLA
 96H  30/1200Z 22.0N  72.6W   40 KT  45 MPH
120H  31/1200Z 24.8N  76.5W   45 KT  50 MPH

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16 minutes ago, NorthGeorgiaWX said:

If she takes the track north of the island, I begin to worry, because regardless of how strong it gets, the tracks are still toward Florida.

Yeah it does look like it all comes down to the degree of interaction with Hispaniola. If it's minimal or even misses to the North then the chances of US impacts go up significantly. 

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9 minutes ago, KingOfTheMountains said:

Yeah it does look like it all comes down to the degree of interaction with Hispaniola. If it's minimal or even misses to the North then the chances of US impacts go up significantly. 

Yep. Gotta thread the needle first, after that, it's a new ball game.

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Does it look to remain a compact storm?  Much less worried overall inland regarding effects if it should be a minimum hurricane and small in diameter.  But the track seems to be thinking hooking NE. I guess that would mean it might pull down some fall air as it reacts?

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